Rolls-Royce and yacht/shipbuilder Lürssen are making a strong case for methanol as an environmentally friendly and climate-friendly fuel for yachts, according to Rolls-Royce's release. They are already working on specific projects, including the propulsion of a Lürssen yacht using mtu methanol engines from Rolls-Royce. The two companies made the announcement at the Monaco Yacht Show, the world's largest exhibition for large yachts.
The companies plan to focus on yachts with lengths of 75 meters and above, which offer great potential for being powered by methanol – ideally 'green' methanol. This is a synthetic fuel produced by taking carbon dioxide (which is harmful to the climate) from the atmosphere and converting it using electricity from renewable generation such as solar or wind farms. The amount of carbon dioxide given off by engines running on 'green' methanol is equivalent to the amount originally extracted from the air, resulting in a 'net zero' carbon footprint.
In addition, methanol engines emit much less particulate than comparable diesels, and their exhaust gases can be vented without undergoing SCR aftertreatment.
The main difference, and thus a challenge for naval architects shipbuilding engineers, is that in terms of calorific value methanol has around 2.4 times more volume than diesel, so the tanks have to be correspondingly larger.
Rolls-Royce is currently developing a methanol engine based on the successful mtu Series 4000. Unlike the diesel engine, whose fuel self-ignites under high pressure, methanol – with its lower flash point – is ignited using a spark plug, in much the same way as a gasoline engine.